Heat exchanger design



Aug. 16, 1955 E. J. RElNoLD ETAL HEAT EXCHANGER DESIGN 5 Sheets-Sheet l Filed Oct. 25, 1.951

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WNIIIII .HlllllllhlllhlllNU nu lellllll l Illy N|l|||||| l Aug. 16, 1955 E, .1. REINOLD ETAL HEAT EXCHANGER DESIGN 3 Sheets-Sheet 2 Filed Oct. 25, 1951 @@@QQQ C Q Q Q Q Q C Q Q Q C Q GGG@ INVENTORS Eugene J. Reinold Lawrence A. Barry BY ATTORNEY Aug. 16, 1955 E, J. REINOLD ET AL.

HEAT EXCHANGER DESIGN 5 Sheets-Sheet 3 Filed Oct. 25, 1951 IN V EN TORS gene J. wrence Eu Reino/d La A. Barry ATTORNEY Patented Aug. 16, 1955 HEAT EXCHANGER DESIGN Eugene 3. Rcinold, Hammond, and'Lawrence A. Barry, Highland, Ind., assignors to Standard Oil Company, Chicago, lll., a corporation of Indiana Application October 25, 1951, Serial No. 253,176

2 Claims. (Cl. 257-236) This invention relates to heat transfer apparatus and more particularly to heat exchangers of the type where1n heat is transferred between two uids, one owing through a bundle of tubes and another iluid flowing through a shell surrounding the tube bundle.

Baled heat exchangers are w'ell known in the art, in one form the baies being arranged substantially parallel to the tubes in the tube bundles, -but in suchan arrangement it becomes virtually imposslble to provide an equal number of tubes in each pass through the exchanger. In another form baffles are arranged transversely to the tube bundle but heretofore it has been necessary to cut the baes in such a manner that the inner or chordal edge of the bale embraces only a segment of at least some of the tubes which are enclosed by the bae. Thisrcondition results in a wear polnt susceptible to fatigue and corrosion, especially 1n an exchanger handling pulsating air or vapors such as 1s the case when the exchanger is used on an air compressor. Many tube failures result at this point of wear.

The object of our invention is to provide an improved construction of Ya heat exchanger of the tube-in-shell type and more specifically an improved construction and arrangement of the baille and tubes systems for so sup` porting the tube bundle as to avoid mechanical failure. Another object of our invention is to provide a bae system wherein no tube is only partially embraced by a given bale. A further object of the bai-lie system 1s to direct and regulate the flow of the uid externally of the tube bundle. An additional object of our invention is to increase the ow path through the heat exchanger without increasing the length of the shell or of the tubes. These and other objects of our invention will become apparent as the description thereof proceeds.

Briefly our exchanger design attains the objects of our invention and eliminates the diiiculties with conventional baffled exchangers by providing 180 bafdes, each succeeding pair Gf which is turned 60 about the magimdmal axis of the heat exchanger. It will be seen that by having a multiplicity of alternate pairs of baies arranged according to our invention each tube is supported at spaced points along its length from several radial directions. Thusin addition to increasing the agitation of the fluid being passed through the shell, this arrangement of baes ties the bundle together in one rigid mass which is mechanically more stable than any conventional apparatus because it resists the vibration of the tubes due to fluid pulsations and avoids any baies which do not completely embrace each tube passing through the baie. Other features and details of construction will become apparent from the following description taken with the accompanying drawings wherein:

Figures l and 1a are sectional elevations of a preferred form of our invention;

Figure 2 is a section taken along 2 2 in Figure l showing a stationary head construction;

Figure 3 is a section taken along 3 3 in Figure la drain and vent plug couplings 20 and 21.

showing the floating head construction with the shell cover removed;

Figure 4 is a plan view of one of the baille elements used in the heat exchanger construction;

Figure 5 is a plan view of a tube sheet showing the pattern of the tube banks; and

Figures 6, 7 and 8 are sections taken along the lines 6 6, 7--7 and 8 8, respectively, of Figures 1 and la, showing the rotation of the alternate pairs of baffles.

Referring to the drawings, we have illustrated one preferred embodiment of our invention in which a tubular heat exchanger has a cylindrical shell 10, a circular stationary tube sheet 11 secured at one end of the shell 10 and a circular floating tube sheet 12 mounted at the opposite end thereof. Six banks of tubes A to F are mounted between tube sheets 11 and 12 and pass through a oating end support plate 13 arranged near the floating end of the shell 10. A convex oating head 14, secured to the floating tube sheet 12, is provided with three partitions 15, 15a, 15b which divide the header into segments or chambers 16, 16a, 16b.

A shell cover 17 comprises a convex cap 18 welded to the shell cover ilange 19 and is provided with threaded The opposite end of the heat exchanger is provided with a stationary head 22 including a convex cap 23, a flange 24, and partition plates 25, 25a, 25h, and 25e, as shown in Figure 2. Threaded inlet 26 and threaded outlet 27 communi cate with the chambers 28 and 29 defined by the stationary tube sheet 11, a portion of the convex cap 23. and the bailes 25a, 25b, and 25e.

With the construction illustrated, a duid entering through inlet connection 26 in the stationary head 22 iows through the top-most bank A of tubes 30 through a reversing chamber 16 formed by the oating tube sheet 12 and partitioned floating head 14, then through the next bank of tubes B arranged counter-clockwise from the inlet bank A and thence into the reversing chamber 31 dened by baes 25 and 25a and a portion of the stationary head 22. The fluid returns through tube bank C to the reversing chamber 16a, and then in series alternately in opposite directions through tube banks D and E, and finally into tube bank F which discharges into header chamber 29 and inally from the exchanger via outlet 27.

The shell 10 is provided with an inlet 33 and an outlet 34 at opposite ends thereof. The interior of the shell 1i) between the oating end support plate 13 and the stationary head 22 is provided with a baie system for directing the ow of the iluid along and about the banks of the tubes. A series of semi-circular baffles 35-43511, 36 36a, 3737a etc. are mounted in the shell 10 transversely to the tube banks A to F. Each of the bales is provided with a set of circular openings 38 for the tubes 30. Each baffle is semicircular and embraces about of the circular cross-sectional area of the shell. Each baiile embraces three adjacent banks of tubes and each successive pair of battles is turned 60 with respect to the preceding and Succeeding pair of bailes. Each bale is provided with the tube-receiving ports 38 and in each instance an entire tube 30 is surrounded by a portion of the baflle.

In assembling the heat exchanger according to our invention, the tubes 30 and a pair of baflles 35-35a, 36-36a, E17-37a etc., the stationary tube sheet 11, floating tube sheet 12, oating end support plate 13, and tie rods 41 are prefabricated as a unit and inserted into the shell 1i). The stationary tube sheet 11 is bolted between the shell llange 40 and the stationary head ange 24. 1n so doing the partitions 25, 25a, 25b, 25e contact the tube sheet 11 to form the four compartments 31, etc. for directing dow through the tube banks A to F.

' The floating end support plate 13 and the stationary tube sheet 11 are tied by means of the tie rods 39 which pass through the battles at their periphery. Brass washers 41 are provided at each point where the rods 39 passthrough a baille. The 180 bales are in turn mounted at spaced points along the tie rods 39 as shown in the Y' drawings with spacer spools or sleeves 46 on the tie rods 39 between the adjacent baffles.

' The iloating head 14 having partitions 15, 15a, 15b is fixed yto the iloating tube sheet 12 by means of the floating head flange 42 and the split ring ilange 43. This tloating Yhead assembly is enclosed by means of the .shell cover 17 which is held tothe shell flange 44 by means of stud Ybolts 45.

With the baille array illustrated, the heat-exchange fluid j n enters the shell via ilanged inlet 33 and flows in a Vsubstantially helical path about and along the tube banks A to F directed by the bales 35'35a, Sti-36a, 37-370, etc. With'this arrangement of bailles and with the arrangement of passes of tube banks A to F, the path of ilow of the fluids is substantially increased in length without a corresponding increase in the over-all length of the heat exchanger. Likewise, by the mounting of the pairs of bailles S-35a, 36-36a, 37-37cz on a 60 rotation pattern, each bank of tubes is supported fromV all direc tions and at a multiplicity of points along theV length of the tubes. The tie rods 39 with spacer spools 46 also support and align the bailles independently of the tubes which pass through the baffles. This structural arrangement of tubes and ballles results in preventing the tube damageV 'which previously koccurred in similar heat exchangers when split bailles were arranged in opposed upper and Ylower pairs.V The described apparatus is mechanically stable to surges of uids through the shell and makes for an eicientheat transfer.

In `Figures 6, 7'and 8, comprising sections 6 6, 7 7 and 8-8 in Figures 1 and la, we have illustrated the Y relative positions of three pairs of bales -35'a,

36-36a, and 37,-37a, each'pair being rotatedrclockwise Y with respectto the adjacent pairs of vbailles. Thus,

referring to Figures 6 and 7, the baille 35a assumes the Y. position of 36a when rotated Vas in Figure 7 and nally is in the position of 37a when rotated an additional 60I Additional pairs, arranged in.V

as shown in VFigure 8. similar sequence complete the exchange,

Although we have described our invention in terms of tuberrbanks intriangular array and with bailles, it is; contemplated that smaller and larger numbers oftriangu lar banksv can be used. For example, we may use from between about 3 and'lZ banks arrangedY in circular sectors of the exchanger. When this is done, however, the shapei of the baille may be altered so that the Weir or chordal edge of each baille can always lie along` a tubeless space',z between banks oftubes. The banks of tubes occupy aliquot circularY Ysectors,Y of the shell and each pair of baffles isangularly displaced about the axis of the exchanger from each adjacent pair of baflles a distance cor-v Y responding to said circular sector.

Thus it will be'seen that the objects of our invention\ have been attained by providing.V the described apparatus. Although we have illustrated and described a preferred form or embodiment of our invention, it will be apparentY to those skilled in the art that in view of our description certain changes may be made in the form of the apparatus without departing from the spirit of our invention as described above or as dened by the appended claims.

Werclaim: j

l. In a tube and shell heat exchanger the combination'of a cylindrical shell, a removable heat exchange core unit comprising aV bundle of six banks of tubes, each bank of tubes occupying about 60 of the cross-sectional area of the shell, a stationary tube sheet closing a iirst end of said shell and supporting said banks of tubes, a oat- V4 ing end support plate across the second end of said shell and supporting a terminal portion of said tube banks, a floating tube sheet for said terminal portion beyond the end of said shell, a convex floating head txed to said Yfloating tube sheet and having co-operating radialV partitions forming return cells for connecting adjacent pairs of tube banks, a partitioned convex stationary head supported in fluid-tight relation to said stationary tube sheet,

said convex floating head and said convex stationary head co-operating to provide series ilow through each of said tube banks in sequence, an inlet and an outlet to said convex stationary head whereby iluids Vlow through said headfthrough each of said'banks of tubes in seriesl countercurrent to fluids ilowing in adjacent banks of tubes, and through saidfloating convex head, and a plu-V rality of pairs of plate-like semicircular apertured bailles arranged transverse toY said tube banks and spaced longitudinally of the said shell, the individual baffles in'each successive pairV being 180 out of Vregister with each other i and each pair of bafdes being rotated as a unit clockwise about 60 out of phase lwith respectV to the next pair of battles, such successive rotation of each pair of bailles yplacing an edge of any bailleV inV a tubeless zone Y between adjacent banks of tubes in said bundle.

2. In a heat exchanger of the tube and shell type Y improvement vwhich comprises the combination of a cylindrical shell, a bundle oftube Vbanks in triangularV array, each bank occupying an aliquotjcircula'r .sector of said shell,V a stationary tube sheet closingk a rst end of said'shellV and supporting one end of said tube banks, a tloatng end support plate within the second end of said shell yand supporting a terminal portion of said tubeV banks, a oating tube sheet about the end Vof'said tube banks beyond the second end of said shell, a partitioned convex stationary head supported in fluid-tight relation to said stationary tube sheet, van inlet to a iirst of said tube banks through said vstationary head, a convex floating head ,xed to said tloating tube. sheet and having cooperating radial partitions arranged in alignment with the tubeless zones between adjacent pairs of tube banks, an

outlet to the last of said Vtube banks through said stationary head, said convex stationary Vheadl Vco-operatingV to provide series flow through said tube banks, whereby lluids ilow through each of said tube banks in seriesV countercurrent to tluid in adjacent tube banks, longitudinally spaced pairs of plate-like semicirular ballles Vraranged transverse to the said tube banks, the individual batlles of each successive pair having ktheir weil-edges in register with each other and adjacent pairs of baflles beinglongitudinally ,spaced in said shell, each succes-kr sive pair of baflles being rotated as aY unit with respect Y to the next pair an angle corresponding substantially to the angle of each said aliquot circular sector occupied by each bank, such displacement ofv each successive pair ff of batlle'spplacing the weir edges of any bae Vina tube-V less zone between adjacent tube banks in said bundle.

References Cited in the le of this patent UNITED STATES PATENTS 1,284,868 Braun Nov. 12V, -1918 1,525,094 Jones Feb. 3', 1925 1,738,848 Starr Dec. 10, 1929 l 1,764,200 Dean .Tune 17, 1930 1,904,875 Metzgar Apr. 1s, 1933 2,223,313 Collins Nov. 26, 1940 2,498,145 v ,Tinker -`.'Feb. 21, 1950 2,595,822 Uggerry May 6, 1952,`

FOREIGN PATENTS Y 25,658 Great Britain Apr. 30, 1907 V200,463 1923 VGreat Britain. July 3,

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